O   Ontogeny The pattern of individual development in a living organism. Opioids Synthetic or naturally occurring chemicals in the brain that may reduce pain and induce sleep. Orchitis inflammation of a testis. Organ Refers not only to an anatomical entity such as the heart or liver, but also to the aggregate of tissues, activities, and channels that constitute the Network of which that Organ is an integral part. Thus the Heart is associated with the Organ Network of the Heart, which also includes the Organ of the Small Intestine as well as the channels of the Heart and Small Intestine. Organ Networks (Zang Fu) Distinct physiological-psychological spheres of function within the organism. The Five Organ Networks correspond to each of the Five Phases. These Networks organize all physical and mental processes and link together all of the structural components of channels, Organs, tissues, fluids, and so on. They are the Liver (Wood), Heart (Fire), Spleen (Earth), Lung (Metal), and Kidney (Water). Otitis media inflammation of the middle ear.